The Fabrication Strategies Of Photonic Crystal Sensors Based On Controllable Wettability Interface And Their Sensing Properties Research

Photonic crystals(PCs)are materials formed by the periodic arrangement of different refractive index media on a microscopic scale.With the unique photonic stopgap,PCs can realize the enhancement of fluorescence signal,and has been widely concerned in fluorescence detection.Its unique and controllable photonic stopgaps allow for enhancement of fluorescent signals.PCs have garnered much attention in the field of fluorescence detection.Recently,self-assembly of nanoparticles(NPs)has become the important way to obtain PCs.Meanwhile,the self-assembly process of NPs can be controlled effectively by substrate wettability.Based on the control of substrate wettability,PC sensors and PC arrays with different morphologies and 3D topologies can be constructed.In this paper,aflatoxins,a common carcinogenic substance,were used as the detection target.A series of fluorescence resonance energy transfer(FRET)detection systems based on PC sensors and PC arrays were constructed in combination with substrate wettability and fluorescent probe.During the drying process of NPs emulsion induced by substrate wettability,the influence of different motion behaviors of gas-liquidsolid three-phase contact line(TCL)on the macroscopic morphology and microscopic assembly structure of fabricated PCs was explored.Fluorescence detection signals were analyzed using high-throughput statistical methods.The relationship between the detection sensitivity,the identification accuracy of multiple targets,and the microscopic assembly structure of PC arrays was systematically studied.PC arrays realized the identification of aflatoxins(B1、B2、G1、G2、M1 and M2).The main work is as follows:(1)The influence of hydrophilic and sliding substrate on the morphology and detection performance of PC sensor was investigated.Based on the control of substrate wettability,a series of PC sensors with different morphologies were fabricated.The effects of different substrates’ wettability on the self-assembled morphology and detection performance of PC sensors were studied.Firstly,a FRET system composed of acridine orange and aflatoxins was established through the selection of probes.Subsequently,PCs with planar structure and dome structure were obtained by NPs self-assembly on the controllable wettability substrate with hydrophilic and sliding,respectively.After the FRET system was loaded on the PCs with different morphologies,the detection properties of PC sensors with different morphologies were investigated.The substrate with different wettability will induce the different motion behaviors of the TCL during the drying process of the NPs emulsion,and the control of the morphology and microstructure of the PCs will be realized.In this study,PCs fabricated on sliding substrate have long-range ordered and high-quality periodic microstructure,the fluorescence signal of this sensor changed the most before and after binding aflatoxin,and the maximum energy transfer efficiency of 1.157 was obtained.Finally,a PC array was fabricated based on the sliding substrate,and the discrimination analysis of six aflatoxins was preliminarily explored.(2)To explore the influence of hydrophilic-hydrophobic patterned wettability substrate on the three-dimensional(3D)topology and discrimination ability of PC array.Based on the FRET system established in the previous work,the TCL orientation movement of NPs emulsion from hydrophobic region to hydrophilic region during drying on hydrophilic and hydrophobic substrate and its regulation mechanism were studied.A series of 3D morphology of high-quality PC arrays with hemispheroid,hexagonal,pentagonal,square,and triangular morphology were constructed.The photonic stopgaps distribution on PCs surface with different morphologies and their enhancement effect on corresponding fluorescence signals were studied.The effects of different morphologies of PC arrays on the discrimination and analysis efficiency of six aflatoxins were investigated.Specifically,the accuracy rates of the six aflatoxins identified by the hemispheroid,hexagonal,pentagonal,square,and triangular 3D PC array were 70%,73%,75%,84%,and 100%,respectively.The 3D triangular PC array has also been successfully applied to distinguish the mixed samples of 6 kinds of aflatoxin mixed with each other,as well as the real aflatoxin samples from moldy potatoes,bread,oats,and peanuts,with an accuracy of 100%.This strategy provides a new idea for the development of multitarget identification and analysis system based on PC arrays.